For what it's worth, the NHL does track stats for penalty shots and shootouts. Filters on the lists are somewhat arbitrary, but I think filtering out the lower sample-rate goalies is useful.
All-Time PS stats for goalies with ten or more PS against
All-Time Shootout stats for goalies with 100 or more shootout shots against
Interestingly enough the average save percentage for both is almost exactly the same. 0.681 for penalty shots and 0.682 for shootouts.
Now PS/Shootouts are not necessarily 100% analogous to a breakaway, but I think for a video game the factors that would make the real-life scenarios different ( goalie and skater time to prepare, no pressure from back-checking defenders, etc ) don't really apply, or don't apply enough to make a significant difference. Even assuming that for "video-game fun" the save percentage is going to be lower than the real-life stats, the goalies in NHL 26 don't really come close to stacking up. From what I've seen so far, if you get a clean breakaway or PS you basically have to try not to score to fail to get a goal. They're significantly worse than they were in NHL 25.